The success of his work with night vision equipment led Ruff to investigate other rarely used photographic equipment and techniques. In 1994 he unearthed the Minolta Montage Unit – a machine used by German police in the 1970s to create composite images of crime suspects. The intention was to blend several images together to create a ‘general’ portrait that would jog the memory of a witness. For the other Portraits series Ruff used four photographs for each image, combining people with different hair colour, eye colour and even male and female models. These works were first presented in the German Pavilion at the Venice Biennale in 1995.